Automatic telephone system



E. A. MELLINGER.

AUTOMATIC TELEPHONE SYSTEM.

APPLICATION FILED FEB. 17. |913.

1,306,829. Patented June 17, 1919.

6 SHEETS-SHEET l.

cfm/Era E. A.'MELLINGER.

AUTOMATIC TELEPHONE sYsElvr.

- APPLICATION FILED FEB. ILQS. l ,$06,829. PatentedJ une 17, 1919.

6 SHEETS-SHEET 2.

E. A. MELLINGER.

AUTOMATIC TELEPHONE SYSTEM.

APPLICATION FILED FEB.17.|913.

Patented June 17, 1919.

6 SHEETS-SHEET 3.

E. A. MELLINGER.

AUTOMATIC TELEPHONE SYSTEM.

APPLICATION FILED FEB. 17| 1913.

Patented June 17, 1919.

6 SHEETS-SHEET 4 WJOTNESSES E. A. IVIELLINGER.

AUTOMATIC TELEPHONE SYSTEM.

APPLICATION FILED FEB. 17. 1913.

1 ,306,829, Patented June 17, 1919.

6 sHEE'Ts sHEET a.

E. A. MELLINGEB.

AUTOMATIC TELEPHONE SYSTEM.

APPLICATION FILED III-:3.11. 1913.

l ,306,829. Patented June 17, 1919.

6 SHEETS-SHEET 6.

EDWARD A, MEIiLINGER, 0F CHICAGO, ILLINOIS.

macteo.

To all whom it 'may concern:

Be it known that I, EDWARD A. MEILINGER, a citizen 'of the 'UnitedStates of America, and resident of Chicago, in the county of Cook andState of Illinois, have invented certain new, and useful Improvementsiti Automatic Telephone Systems, of which thel following is aspecification.

This invention relates to improvements in telephone systems andapparatus therefor,

and more particularly to automatic or senll automatic telephone systemsor. combined manual and automatic or semi-automaticv systems of the typein whichthe operation of an automatic switch or automatic switches iscontrolled -by a plurality of selective actions at the callingsubstation.

According to one feature of the invention a calling device providedwhich is so arranged land constructedl that when any one of a certain.number of parties is to be called a single select-ive action on thepart'of the calling party suffices to enable him to call therequiredparty instead of his having to effect a number of selective actions, ashas heretofore been necessary, the plurality ofI selective actions onAvthe part of the calling subscriber being dispensed with by asettingiup operation.

According to another feature of this invention means are providedwhereby after call is effected by anyA type of callingdevice,

and before the calling-party' has removed hisV receiver from thel'hook,an indication is given him when the called partyfremoves his receiverfrom the hook.l Furthermore, `means are provided for releasing allV ofVthe switches that have been operated if the `cal1ed\ -partv is busy.and for giving a signal tothe callto indicate .that the called party Lhorizontal positions, engaging -corresponding party is busy.

The form of apparatus forlcarrying the Dicker No; 1298 of 1910, thoughthe appara-- tus can easily be' adapted, as'hereinafter referred to, for-use in other types of automatic or4 semi-automatic telephone` systems.

The invention will be lmore readily understood fromA the followingdescription,

taken in yconuec'stionrwith ythe accompanyingdrawings which illustrate,by way of exam,-V

Specicationo Letters Patent. Patented than@ 1W, 1919, Application filedFebruary 17, 1918. Serial No. 748,811. l

4 are details on an enlarged Fig. 6 vis a section on the line 6-46`Fig.. 5. v l 1g.v7,1s la side elevation of the same, the casingand'somexother parts being in sec-V tion:

' F1g. 8 isa' part section on the line 8--8 of Flg. 6

Fig. 9. isafsection on an enlarged scale .l

ofpart of the gea-ringI employed. n

Fig. 10 is a sideelevation of parts which are addedA to the callingdevice shown in Figs. 5 to'v9 for carrying out'certain other features ofthis invention.- Fig. 11 is a front viewof the same. Fig. 12 is adiagrammatic view of apparatus and circuitsfor carrying out cert-ainfeatures o f this invention. A

' Fig. 13 1s a diagram showinga modicai tion which may be made in thecircuits.

Like reference numerals and letters are in use throughout' thespecification to indicate the corresponding parts.

Referring now'to Flgs. 1 to 4, inc1usive,a vertical board 1 is provided,having arranged 'on its two vertical sides racksl 2, 2.

A bar 3 has attached 'to' its two ends, re-

spectively, cords 4 which pass over pulleys- 5 at the top of the boardand have their l other ends attached to weights 6. The bar 3' can,'therefore, be easily set in various ing teeth in the'two racks 2, 2.Slidable on the bar`3 is a block 7, preferably of insulating material'.Thespring 8, as shown in Fig.- 4, which is an `under plan view of the.blocl5\7, is cut away at'its ends so as to leave a U-shaped portion,andthe spring9 is cut away so as to leave a portion 'betweenjthe twolimbs of the'spring 8.

ley 10 is arranged and over this pulley *passes acord one end of 4whichis attached to the piece 7I and the other ,end to a weight The springsfSand 9` -are connected to suitable a terminals, as shown. On an extensionof the roda pul- -wheel 12. The spur wheel 12 gears with a` smaller spurwheel 13 carried on a spindle rotatable in the extension of the bar 3,and

this spindle carries a governor 14. Pins 15 are inserted in the board inhorizontal rows,

so that when the bar 3 is set in any given.

out of contact therewith to a position 19, Y

shown in broken lines.' A rod or bar 20 is pivoted to the arm 16 and isslidablein guides 21. The ends of the bar 2O extend beyond theblock 7and are adapted to .engage the sides of the racks 2 and 2 when the block7 is moved as hereafter referred to. Thel switch arm 16x and the contact18 are connected, respectively, to the two terminals which are connectedto the springs .8 and 9.

At the bottom .of the board a portion is cut away and a fixed spindle 22has mounted on it four cylinders 23, 24, 25 and 26, which cylinders arefreely rotatable on said spindle. Each c linder has attached to it atoothed wheel 2 into the teeth of which the end of a spring 28 canengage so as to hold the cylinder in position, but allow4 of lits beingturned easily by hand. Pins are v arranged on each of the cylinders asfollows: On successive generating lines of the surfaces there arearranged, respectively, one pin, two pins, three pins ten pins.Thesurfaces ofthe cylinders are just flush ,y with the front surface ofthe board, so that the rollers can be set to provide rows of pins, asarranged in the upper part of the board.

The device described, as hereinbefore mentioned, is particularly adaptedfor use inl an automatic telephone system of the two-Wire type, such asdescribed in the specification of said British Letters Patent No. 1298of 1910, and the method of using it and of setting up the calls will nowbe described. The springs 8 and 9 are connected in series with theordinary calling device, or in place ofthe ordinary calling device. Thevarious subscribers that it is desired to call, for example, those mostfrequently desired to be called by the particular calling party, haveallotted to each of them one particular row of pins. For example, inFig. 1 pins are shown in the first level forcalling (reading from rightto left) the number 5323 and in the secondi level 'the number 6614. Itwill be understood that the pins of the particular subscriber to becalled are kept permanently in the board. If this calling party desiresto call the subscriber allotted to the first level, for example, andagainst -which level the called partys name appears, it is onlynecessary lWhen the block reaches the right-hand side of the board, theright-hand end of the rod 20. engages the right-hand rack 2, and theswitch arm 16 is moved to the position shown in broken lines at 19.' Theshortcircuit is therefore rem'oved from the springs 8 and 9, and as theblock returns the pins 15 cause the necessary impulses to be sent. Thatis 'to say, there are five breaks in the circuit, then a pause, thenthree breaks, then a pause, then two breaks, then a pause andthen Vthreebreaks. When the block 7 reaches the left-hand side of the board, vtheleft-,hand end of the rod 2(1)'engages the left-hand rack 2, andvconsequently the Switch arm 16 is moved over to make con tact with thecontact 18, thereby leaving the block 7 ready for the next call. Thereturn movement of the piece 7 is governed by the governor 14.

It will thus be seen that after the pins arev set up for the kcalls ofparticular parties to be called the calling part does not have toconsider what the num er of the called party is, but merely has to'movethe bar 3 to the particular osition allotted to the particular party -tobe called.

The cylinders 23, 24, 25 and 26 are pro vided so that, instead ofalteringthe pins fixed in the board, a call may be set up and left setup for any length of time desired. For this purpose the cylinders aremerely rotated-so that the particular groups of pins come into thehorlzontal level over which the springs 8 and 9 move when the bar 3 isin its lowest position. i

The apparatus described is for calling a number of a called partyconsisting of four digits, but it is obvious that the ap aratus may beconstructed for calling num ers of any number of digits. Referring nowto Figs. 5 to 9, inclusive, another calling device operating on theprinciple of the calling devicedescribed in connection with Figs. 1, 2,3 and 4 will now be described. Mounted on a suitable base 30 arestandards 31 and rotatable in the standards is a shaft 32 which is ofsquare crosssection beyond the parts fitting in the bearings. A numberof disks 33 are mounted on the shaft, and for this purpose the diskshave radial slots 34 and in these slots are provided springs 35. Collars36 are provided on the shaft 32 and the disks it bemoese@ tween thesecollars. They can be slipped onto the sl1aft,the springs 35 holding themin position. y the disks 33 are arranged rings 37 held in positionbyscrews, and between these rings and the disks are arranged radialpins. or strips 38.v These pins can be moved radially and are curved attheir inner ends, the

depressed portion bein adapted to fit into one of two correspon mgannular depressions 39 in the disks (see Fig. f'8 andthe lower portionof the disk or the right-,hand side, of Fig. 7). -The 'ins 38 can,therefore, be placed in one or tlie other of two positions-' that is, sothat they either project or do not and slidable lon this bar is a block41 of insulating material. On the under side of the piece 41 isscrewed aspring 42 which can be depressed by al spring-pressed handle orvplunger43. The springl 42 is provided with a tooth 44 whichis a apted to engagein slots 45 lin the under side of 'the bar 40. TwoA springs 46 normallyin contact are lsupported on the block 41, and outside of these twosprings are two springs 47 insulated therefrom but normally keepin thesprings 46 in contact.. The springs 4 extend beyond the springs 46, asshown, and two guard-pieces 48A are arranged -outslde them.

y 0n the pins 38 forcing the springs 47 out of contact the springs 46also separate.

Mounted on a spindle 49 rigidlv secured to the standard 31 is an arm 50.Rotatable on the spindle 49 is a ratchet wheel 51 rig-l idly secured toa spur wheel 52.- A springpressed pawl 53 is carried by the arm 50 andis adapted to engage the ratchet wheel 51. A` clock spring 54 surroundsthe spindle 49 and has one end attached thereto, the outer end of thespring` being attached to a pin '55 4on the arm 50.) The spur wheel 52gears with a spur wheel 56 carried on the shaft 32. The shaft 32 alsohas rigidly attached to it a spur wheel 57 which gears with a I spurwheel 58 mounted on a spindle rotaonly in one direction.

table in a bearing formed by an extension of the standard 31.A Mountedon the latter spindle is a worm wheel 59, which worm wheel meshes with aworm 60 on the spindle of a governor 61. Attached to a suitablestandard' 62 is a spring 63 having an angular projection 64 on itscurved end 6 5, which latter is adapted to engage inthe slot 34 of thedisk 33 adjacent to the gearingdescribed.y

Mounted on the shaft 432 is a ratchet wheel 66 with which engages a sring-pressed pawl 67, so'as to allow the sha t 32 to rotate Theapparatus is provided with a casing v68 having a slotv 69 to'allow ofthe movement of the arm 5 0, and on the top of the p Around thecircumference of project beyond the.periphery ofthe' the end 65 of thisspring in I diu-m of the spur wheels casing are provided tablets 70carrying the names of the subscribers who can be called. The block 41 isprovided with a pointer .71 whichA can be set opposite the name of thepartlcular subscriber to bey called and indicates when the block 41 isinthe correct posltion for so doing. 4

1 Each of the disks is allotted to a particuar so set as to effect thenecessary impulses to o erate the switches. For example, the disk s ownin Fig. 6 is set to callthe subscriber whosefinumber is 5423. Thesprings 46 are j connec/ted 1n serles with an ordinary call-mgotherwisethe guard-pieees 48 would engage the disks and preventmovement.y When the block 41 is in tlie proper position the plunger 43lsreleased, the tooth'44'engaging the corresponding slot 45 in the underside of the bar 40. The arm 50 is' then depressed. During this movementthe pawl 53'slips over the teeth of the ratchet wheel 51,'the shaft `32being prevented from rotation, as'also the ratchet wheel 51, by means ofthe ratchet wheel 66 and the pawl 67. In the position of the arm 50 itengages the pro# j ectlng portlon 64 of the spring 63 and keeps U theslot 34 of the disk adjacent Vto the gearing. After a small normal ymovement of the arm 50 the end 65 of the i spring 64I moves out of theslot 34. During the downward movement of the arm 50 the sprlng 54 is`wound up. On the release of the arm 50 it is returned by the spring 54andthe pawl A53 rotates the ratchet wheel 51, and thereby the shaft 32through the me c 52 and 56. The projectlng pms 38 separate the springs47 and thereby thus sending the necessary impulses 'to the line toeffect the automatic switching. The

governor 61, it will be seen, controls the,

speed of the disks l33 as the arm 50 returns permit the springs 46 toseparate,

to normal position.. J ust before the arm 50 reaches its normal positionit engages the spring 63, which is thereby depressed and enters the slot34 in the disk adjacent to the gear as soon as'the latter and with itall of the other disks return to normal position, thereby preventingoverrunning of the disks. 1n the construction of calling device so fardescribed the arrangement has been such that a pair lof springs areseparated to send impulses. However, it is obvious that in any of theconstructions of apparatus it can be arranged so that contacts would beclosed, as would be necessary, for example, in a three-wire type ofStrowger or other similar system, additional contacts being provided forsending supplementary impulses that may be required.

In practice, the bulk of the calls of a telephone `subscriber are madeto a very limited number of subscribers, say twenty or thirty, and acalling device constructed according to this invention enables thesesubscribers to be called with a single selective operation on the making1t simpler and easier to effect a call and tending to prevent errors inmaking a call. A calling device constructed according to this inventionis, therefore, particularly applicable for use with telephone systemshaving a large number of subscribers, as in this case the subscribershave numbers consisting of several digits and consequently necessitatingnormally several selective operations on the part of the calling party.

As hereinbefore mentioned, according to anotherfeature of this inventionmeans arer provided whereby after a call is effected by any type ofcalling device, and before thc calling party has any necessity forremoving hisreceiverfrom the hook, an indication is given him when thecalled party removes his receiver from the hook. Also, if necessary ordesirable, an indication is given to thecalling partyif the called partyis busy. Furthermore, if the called party is busy all the switches thathave been operated are released, this obviously being an additionaladvantage, as it enables the switches to deal with a larger number ofcalls than would otherwise be possible. Should a calling device beconstructed and arranged so that the call is repeated at intervals, ashereinbefore referred to, it may be unnecessaryl to provide means forindicating when the called party is busy, the calling device beingarranged to operate until the calling party gets the indication that thecalled party has removed his receiver from the hook. According to thepreferred method of carrying this part of the invention into effect, thetwo indications to be iven to the calling party are effected broa ly bythe following means: In a two-wire type of automatic telephone-system,as described, for example, in the specification of said British LettersPatent No. 1298 of 1910, when the called party removes his receiverfrom'the hook the direction of flow of current to the calling party isreversed, and this reversal of current is employed to indicate orcontrol the indication that the called party has removed his receiverfrom the hook. To give the indication when the called line is busy theconnectors are so constructed and arranged that the line of the callingparty is opened. this opening of the line indicating or controlling anindication to the calling party that the called party is busy. Theopening art of the calling party, thereby iof the calling partys line asjust referred to also serves to release all the 'switches op- @rated bythe calling party.

One specific method of carrying this part of the invention into effectwill now be described in detail in connection with a calling device ofthe type shown and described in connection with Figs. 4 to 9, inclusive,of the accompanying drawings.V In Figs. 10 andi '11 are shown themodification or addition to the calling device which is necessary forcarryingthis part of the invention into effect'. Attached to onestandard 3-1 is a bracket carrying an electromagnet or relay 81 and apolarized electromagnet 82.

Attached to the bracket is a block of insu-v net 81, on being attracted,forces the. three springs 87, 88 and 89 into contact. When current flowsin one direction through the polarized electromagnet, the armature 94holds the armature 93 of the electromagnet '81 in its attractedposition. Fig.'12 shows diagrammatically a calling substation F providedwith a calling device of the type shown and described in connectionwith. Figs. 5 to 9, inclusive, of the accompanying drawings, and havingthe additional apparatus described in connection with Figs. 10 and 11,and thetrunk line leading to a called substation F', thecall bein shownas completed. So far as the ordinary substation apparatus and theautomatic apparatus employed in effecting a connectionl is concerned,the circuits correspond to those shown in the specification of saidBritish Patent No. 1298 of 1910, all circuits and apparatus beingomitted4 which are not directly concerned in the present invention. AtH, K, L and H is a line switch, selector, connector and line switch,respectively, as in the specification referred to. The connector L issimilar to the connector L of the speciminal of which is connected tobattery B.

The relav 97 is provided with three'contact springs and the uppertrunkis broken, one side being connected to the two springs 98 thetalking conductors. current in the polarized electromagnet82. an bell275. or givesany Upon the relay 97 being energized the spring arated, sothat the-line isop v99 and into contact 100 is moved out of contactwith'the Spring. with the spring 98. The

three springs just referred-td are widely seppreciable time, or', toobtain' along break,

-any suitable dash-.pot maybe connected with the armature of'therelay.

The substation F provided with the orferred to, namely, a telephone hookand l a ringer and a'coiidenser." At the telephone hook an auxiliarycontact 101 is provided,

this contact 101 and the upper contact being vso constructed that theswitch hook, on rising, does not break contact .with the contactV itmakes contact with theupper contact.' l

- 4The subscriber Idesir'ingto make a call sets;

the block carrying' the impulse springs46 opposite the name of thesubscriber to be called, as described in connection with Figs.

5 to 9, inclusive. il-Ie then depresses the arm 50 and on its retlirnmovement the disks 33 begin to move with the shaft 32. Before anyimpulses are senti/he arm91 allows the-two springs 84 and 85th-come intocontact.- This closes a circuit over-the line from the lead 157, contact101, impulse springs 46, springs 84 and 85, sprind s" i8 and 86 to theline 158.

The line switch is consequently. operated Y in the ordinary manner andas described 1n the specification referred to. The impulses are thensent to operate the selector K and the connector L. i'ijDirectlyafterthe. sets of impulses have been completed the arm 9 2 separates thesprings 86 and 87 and immed1 ately closes the springs 87, 88 and 89. Ac1rv cuit is vthereby lclosed throughthe electrothe hook'and the linereceiver hookl does not break contact with .65

vby means v'of the usual magnets 81 and 82,`this circuit being' from theline 157, contact 101, impulse springs 46,. spring 89, spring- 88,lmagnet 81,y magnet 82' andthe line 158.f.=5'-\The magnet 81 attractsits armature and holds the springs 87,88 and 8 9 in contact 'and -tliespring 87 out of contact If, -the called `'subscriber answers hereverses the direction of the current 4in the calling subscribe'rislinein the usual .manner back bridge relay (not shown) which operates thesprings 273 to reverse the connection of the relay 274V to This reversesthe upon its armature moving, itstrikes a other signal to indicatetolthe calling subscriber that the calledl subscriber has answered. Thecalling subscriber can then removev his Areceiver from is not broken, asthe the Contact 101 "until 'it makes contact with 1 scribed. dinaryapparatus, asinthe specification rev9 5. 'and 96, thereby ener'gazing-Jvf contacts therefor, 'a receiver andtransmitter,4

. ferred to.

may be employed. In'

. thesprings 105 and 106.

' into effect, those the upper contact. l Upon the hook completingitsupward movement'thecircuits of the magnets 81 afnd` 82 are broken, sothat u on the hanging up of the, receiver the switc es switches arereleased in a' manner'to .bedef The relay'272is energizedifthe calledlineV is busy. This closes-the springs e-l'elay 9 so-"ythatcqnmct betwnthe spingsee and 100 ,is firstI broken and@ then F'after someinoperated. The 4relay 97 `has its springs separatedv tol va somewhatconsiderable distance,

so that-the line Ais opened for a comparatively long interval of time',`as hereinbefore re- Instead of arranging the springs at some distanceapart,as jfustmentioned, or of providing a-.dash-potjfor 'the armatureof the relay 97, the arrangement shown in Fig. 13 place of the relay y97there is arranged a relay 102-w-hich is quick tofenergize'but slow'todenergize. The line is' broken and connected to .the` two contactsprings 103 and 104 of this relay, while the circuit of the relay 1.02is completedthrough When; therefore, thesprings 95 and 96 are'closed bythe ener- 'giz'ation of the relay 272,'the -relay 102 is energized, butits armature breaks .its own circuit so that it denergiz'es slowl andthe connection between two parts of t e line is not completed for Soniellittle time. To aid in this the armature of the relay 102 m-ay beloaded, so that it does notmove until the energizing current has nearlyreached its maximum value. Thel denergization of the relay 8l may servetooperate a bell 276 or give any -other suitable signal to indicate thatthe called line is` busy. Itmay be noted that the'bells 275 and 27 6 maybe of differentsize or may be arranged in any manner to give differentsignals.'

The circuit at the connector is temporarily opened, as just described,and not perma nently opened, as vmight be more easily anranged, for theyreason that if the circuit were permanently opened, upon ,a call beingmade in the ordinary way'to a vbusy subscriber, the calling subscriberwould not get the ordinary busy signal.

j It is obvious that various modifications can be made in carrying thevarious features given above being merely by way of example.`

Y l. In a telephone" system, means for connccting a calling and a calledtelephone line, means under the control of the calling telephone tosignal the called telephone, means for indicating to the calling partybefore he removes-his receiver from the hook that the called party hasanswered.

2. In a telephone system, aplurality of subscribers lines, meansincluding auto- 'matic switches for establishing connection between twoof said lines, and means for indicating to a calling party before he hasremoved his receiver` from the hook that the called party has answered.

3. In a telephone system, a plurality of subscribers lines, meansincluding automatic switches for establishing connectiony switcheswithout removal 'of the receiver from the hook at the calling station, as1 nal at the calling station, means controlle the response of the.called subscriber for reversing the currenton the calling line, and

means controlled by said reversal of current for operating said signalbefore the callingsubscrlber has removed h1s recelver from the hook. 4

5. In a telephone system, a plurality of subscribers lines, means forestablishing a connectionbetween two of said lines, a signal on thecalling line, and means for positively operating said signal when anattempt is made to establish connection with a busy line to therebyindicate to the calling subscriber that the called line. is busy, a

source of current for supplying current to the line for talking, meansfor removing said source, said signal responsive to the removal of saidcurrent.

6. In a telephone system, a plurality bf subscribers lines, meansincluding automatic switches for establishing a connection between twoof said lines, a signal on the calling line, and means for positivelyoperating said signal when said automatic switches attempt ton establishconnection with a line which is busy, a source of current for supplyingcurrent to the line for talking, means forv removing said source, saidsignal responsive to the removal of said current. l

7. In a .telephone system, a plurality of subscribers lines, means forestablishing a connection between two of said lines, a signal on thecalling line, means for positively operating said signal when an attemptis made to establish connection with a busy line to thereby indicate tothe calling subscriber that the calledline is busy, and means forautomatically releasing said connection when said signalI is operated,alsouree of current for supplying current tothe line,

for talking,`means for removing said source, said signal responsive tothe removal of said current. I

`8. In a ytelephone system, a plurality of subscribersI lines, meansincluding automatic switches for establishing a connection between twoof said lines, a signalen the calling line, means for positivelyoperating said signal when said automatic switches attempt to establishconnection with. a line which is busy, andv means for automaticallyreleasing said automatic switches when 'said signalis operated, a sourceof current for supplying current to the line for talking,

means for removing said source, said signal V `responsive to the removalof said current.

9. In a telephone system, a line, atelephone Ifor said line,pau'tomaticprogressively movable trunking means for said line for eXt'ending aconnection toward a called line, an impulse sender at the telephone forcontrolling said means, a battery for operating lpurposes, a signal atthe telephone responsive to, current of one kind over said line tooperate the signal in one manner to indicate that the called line isbusy and responsive to eur- `rent of another kind to operate the. signalin a' different manner to indicate that the called party has answered,another signal at the telephone, said signal yresponsive to current of adilfere'nt character to indicate'that the calledline is busy.

Signed by me at Halton House, 20-23 Holborn, London, England, this 18thday'of January, 1913.

Y p EDWARD A.\M-13LL11\IG.1+3R.f Witnesses: i i

ALBERT JONES, WILLIAM S. COLLINS.

